Imposition question relating to FusionPro & Digital StoreFront

Wondering if I could get some help please. I am running FusionPro and Digital StoreFront for custom Bus cards etc and am coming up with an issue regarding the imposing. My FusionPro file contains a .fpi file which works perfectly, however I want to choose when to apply this to the variable file, currently it happens at the start so that my customer when looking at a preview through DSF sees the imposed version of their job, is it possible to apply the .fpi file after this?

Any help would be appreciated. I am running DSF version Version 4.8.6.10329 and version 7.1 FusionPro.

I'm not a DSF user, but I know that with the portal solution we use, it is possible to include the name of a specific .dif file in the command-line call to FP Server. The .dif file specifies the .fpi file to use so we can produce a 1-record proof for preview purposes, and then (after a confirmation by the end user in our case) 2nd call can be made naming a different .dif file which includes the imposed .fpi reference. Perhaps you could check with DSF support to determine how to modify its communication with FP Server?